FURTHER ADVANCES TOWARD A MODEL OF GYPSY-MOTH (LYMANTRIA-DISPAR (L)) EGG PHENOLOGY - RESPIRATION RATES AND THERMAL RESPONSIVENESS DURING DIAPAUSE, AND AGE-DEPENDENT DEVELOPMENTAL RATES IN POSTDIAPAUSE

Measurements of respiration rates were used to support a three-phase model of gypsy moth egg development. Respiration rate was measured on individual eggs that had been reared for 0-155 days at 5 degrees C following diapause initiation. Diapause termination was indicated by the dramatic increase in respiration rate that began approximately 95-125 days after diapause initiation. Respiration rates at 25 degrees C increased each day by approximately 0.0054 mu l CO2/24 h during diapause. After diapause termination respiration rates increased each day approximately 0.1379 mu l CO2/24 h. Eggs were equally responsive to temperature changes during diapause acid postdiapause. A 10 degrees C increase in temperature resulted in a 2-fold increase in respiration rate. Developmental rates in postdiapause were found to be age- and temperature-dependent. The initial developmental rate parameters and a temperature-dependent rate change parameter were estimated empirically and a composite function was derived to describe the age- and temperature-dependent behavior of the developmental rate response. Modeled rates increased from 0.0 and 0.078 day(-1) at postdiapause initiation to 0.01 and 0.20 day(-1) at physiological age 0.95, at 5 and 30 degrees C respectively.